Non-pneumatic resilient tire

ABSTRACT

A non-pneumatic resilient tire which derives its capacity to bear a load from laminated elements capable of supporting bending moments. The laminated elements include a stack of resilient sheets superposed and separated by a layer of rubber adhering to the latter, forming a beam capable of undergoing bending stress.

BACKGROUND OF THE INVENTION

[0001] The present invention concerns vehicle wheels of any type and, inparticular, a non-pneumatic tire designed to be capable of bearing aload without inflation pressure.

[0002] It is known that the reinforced rubber tire inflated to workingpressure has come into common use, so great are its qualities of comfortand sturdiness. It has been successfully adapted to applications asdifferent as passenger vehicles, construction equipment, airplanes,motorcycles, farm machinery, heavy trucks, etc. The inflation pressuremakes it possible to bear a load and distribute it on the surface.

[0003] Although the reliability of a pneumatic tire has becomeremarkable, it is known that the risk of a flat is not totallyeliminated. The problem is that, in case of loss of inflation pressure,or even more insidiously in case of a substantial reduction of inflationpressure, the tire is no longer able to render the service for which itis designed under good conditions. Hence, there has been a multitude ofproposals for non-pneumatic tires (see, for example, U.S. Pat. No.5,050,656), the object of which is to eliminate the main cause of tirefailure (flats), but which have not come into use for lack of being ableto offer a sufficient level of comfort and/or endurance and/or capacityto bear heavy loads. Hence, there have also been numerous proposalsaimed at providing tires with a greater capacity to roll temporarilywithout inflation pressure, for example, as described in U.S. Pat. No.5,535,800.

[0004] The proposal cited above has, however, the disadvantage that itis complicated, if not impossible, to design a tire whose sidewallsremain resilient and can tolerate suddenly mounting a curb withoutdamage. In fact, the reinforcing elements incorporated in the sidewallsrisk being bent, in case of very marked stress, to the point that theirradially outer end joins their radially inner base. In that case, ifthose elements are locally gripped to the extent of resulting in verysmall radii of curvature, their breaking point or their elastic limitwill be exceeded, depending on the materials used. The object proposeddoes not therefore provide sufficient safety, since there is a stronglikelihood that the tire will be destroyed (or even worse, locallydegraded in a dangerous but not immediately apparent manner) bycertainly extreme but not abnormal stresses (shock on a sidewalk curb).An ordinary tire, even when greatly deflated, tolerates these stressesmuch better due to its very flexible sidewalls, incapable of bearing theload by themselves.

[0005] The state of the art shows, by wavering between radical solutions(non-pneumatic tire wheel) and the solutions providing tires with alimited capacity to roll without pressure, that the problem of possibletire failure is extremely difficult to solve.

[0006] Furthermore, even without tackling the problem of failure, a tireas currently designed presents other disadvantages to which we havebecome accustomed for a very long time. It can be observed that a beadis so designed that it can be mounted and demounted from the rim, whilebeing able to transfer the working stresses between the tire and the rimthrough sufficient tightening of the tire on the rim. This requires arather delicate adjustment. It results in the rather solid and rigidconstruction known. But considering service rendered the users, there issome waste of material, for the use of a portion of same can beexplained only for securing the mountability and demountability of thetire.

[0007] It is also known that the compromise between comfort (all thegreater the more flexible the sidewalls) and performance (precisesteering, which results in stiffening the sidewalls and/or in developingsmaller and smaller sizes for passenger vehicle tires) is very difficultto arrange. It is also known that there is a great propensity for tiresof a passenger vehicle to lie down under the front wheel on the outsideof a turn in case of high transversal acceleration. In this case, thetire works quite poorly, letting the tread go too much and bearing onthe road with the shoulder of the tire.

SUMMARY OF THE INVENTION

[0008] The object of the present invention is to propose a non-pneumatictire that can truly be used without inflation pressure, which will becapable, like the pneumatic tire, of bearing a substantial load whileproviding good comfort, good adherence and good capacity to transmitconsiderable lateral thrusts. It is a question of proposing analternative solution to the pneumatic tire. It is not simply a questionof providing a tire with the temporary capacity to run flat.

[0009] The invention proposes a resilient non-pneumatic tire having anaxis of rotation and essentially containing a tread carried by aresilient bearing structure radially situated inside said tread anddefining, at least partially, an inner cavity of revolution, saidbearing structure comprising:

[0010] a zone of attachment radially on the side of the axis ofrotation, for the locking of said bearing structure on means ofconnection to a hub, and said zone of attachment being axially placedbetween the lateral limits of said bearing structure, said attachmentzone being designed for contacting said means of connection to a hub,said means of connection to a hub being designed to form a rigidassembly,

[0011] a plurality of support elements, extending essentially crosswise,placed between the zone of attachment and the tread, said supportelements being juxtaposed circumferentially and distributed all aroundthe circumference, the support elements being fitted in said zone ofattachment, each support element containing a bundle of superposedresilient base pieces, separated by a layer of elastomer adhering toeach of the base pieces, so as to form a beam capable of undergoingbending stress,

[0012] an interconnecting structure between the support elements,arranged so that a portion of a radial stress of a support element istransferred to the adjacent support elements circumferentially, whileallowing differences in displacement between adjacent support elements.

[0013] The capacity to bear a load, in the proposed non-pneumatic tire,is due essentially to the support elements. Distributedcircumferentially, the support elements successively come into play forcontribution in taking up the load when the non-pneumatic tire isrolling. Several preferably come into play at the same time in thefootprint. The support elements are transversely oriented andessentially stressed on bending in order to make their individualcontribution to taking up the load (that is, the so-called “Z”stresses). Other stresses do exist, but it will be apparent that theelements are essentially stressed on bending.

[0014] Turning to the embodiments of each support elements, it will beshown that they comprise a bundle of flexible base pieces each of whichis ribbon-like. The flexible base pieces are stacked radially, withinsertions of elastomer adhering on each of the flexible base pieces.The beam thereby built is able to sustain bending in a radial plane.This feature of the support elements is however by no means limitative,namely if it is noted that the support elements have to sustain otherdeformations, since they do not all deform in a identical waysimultaneously, as it will become more apparent hereunder. By describingthat the means of connection to a hub form a rigid assembly, it isintended to point out that the whole deflection between the ground andthe axis of rotation comes from the deflection of the non pneumatictire, and not from a rim, a wheel or any suitable device for connectingto a hub, just like a conventional pneumatic tire with respect to itswheel.

DESCRIPTION OF THE DRAWINGS

[0015] The invention is explained more in detail by the description ofthree nonlimitative working examples illustrated in the attachedfigures, in which:

[0016]FIG. 1 shows a radial section of a first embodiment of anon-pneumatic tire according to the invention, having a tread of convexshape, resembling the tires designed to operate accepting wide angles ofcamber;

[0017]FIG. 2 is an enlargement of the part surrounded by circle A inFIG. 1;

[0018]FIG. 3 shows the same non-pneumatic tire deformed to anintermediate deflection level;

[0019]FIG. 4 is a section along IV-IV in FIG. 1;

[0020]FIG. 5 is a section along V-V in FIG. 1;

[0021]FIG. 6 shows a radial section of a second embodiment of anon-pneumatic tire according to the invention, having a tread of ratherflat shape, common for tires designed to operate at zero or very narrowangles of camber;

[0022]FIG. 7 shows the non-pneumatic tire of FIG. 6, deformed to anintermediate deflection level;

[0023]FIG. 8 shows a radial section of a third embodiment of anon-pneumatic tire according to the invention, also having a tread ofrather flat shape, common for tires designed to operate at zero or verynarrow angles of camber;

[0024]FIG. 9 shows the non-pneumatic tire of FIG. 8, mounted on adifferent rim;

[0025]FIG. 10 is a partial sectional perspective, diagrammaticallyshowing essentially the structure of the non-pneumatic tire according tothe third embodiment without load, in a state free of any stress;

[0026]FIG. 11 is a partial sectional perspective, showing essentiallythe deformation under load of the structure of the non-pneumatic tireaccording to the second and the third embodiments.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0027]FIG. 1 shows a non-pneumatic tire having a tread 11 with agenerally curved shape. The wall of the tire essentially contains twoparts called “first and second structure parts 11I and 11E.” These firstand second parts are radially superposed and form two springs acting inseries and are respectively arranged radially inward and radiallyoutward. One characteristic of this first embodiment is the pseudohingeseparating the first 11I and second 11E structure parts, whichconstitutes a zone of lesser bending strength. This zone of the tire, byits constitution, does not oppose or just slightly opposes folding, thatis, the relative rotation of the end parts of the first radially innerstructure part and second radially outer structure part. The ends ofeach of the first and second bearing structure parts are situatedroughly at the lateral ends of the bearing structure. The supportelements consist of laminated elements 12. Each support element of thefirst bearing structure part goes from one lateral end to the otherlateral end. The profile of the radially outer surface resembles that ofmotorcycle tires.

[0028] The laminated elements 12 are capable of supporting bendingmoments to a much greater extent than the cords—even wires—ordinarilyused to reinforce tires. The laminated elements 12 embody a stack ofresilient sheets 13 superposed and separated by a layer of rubber 15(see FIG. 2). It is suggested here to use rubber as elastomer but it isnot limitive. The take-up of a load makes each of the sheets 13 workbending and the rubber of each layer 15 work shearing. The thickness ofeach layer 15 (which can, furthermore, vary), the thickness of eachsheet 13 (which can also vary), the number of sheets, the modulus ofelasticity of the materials used for the sheets, the modulus ofelasticity of the elastomer used and the arrangement of the sheets aresome of the parameters making it possible to adjust the properties ofthe non-pneumatic tire (which means adjusting the curve givingresponsible force to the capacity of the tire to bear a load dependingon deflection of the tire, commonly described by the expression“load-deflection curve”).

[0029] The sheets are, for example, constituted essentially by athermosetting or thermoplastic resin matrix, reinforced by fibers mainlyarranged longitudinally in each sheet, that is, parallel to a meridianplane (that is, a plane containing the axis of the tire) in thenon-pneumatic tire. Glass fibers yield good results, but fibers ofanother kind could also be used, depending on the advantage contributedby their characteristics. One can imagine numerous working variants ofthe sheets. For example, as can be seen in FIG. 2, each sheet is formedby the superposition of bands 14 glued to one another.

[0030] The bands can, for example, be glued in place, that is, in thenon-pneumatic tire being manufactured. This is one solution among othersfor making sheets without preload or at least with a negligible preload,when installed in the non-pneumatic tire with the desired curvature, asdrawn in FIG. 1. The advantage of thin bands is that, with any method ofmanufacture for said bands, they can easily be made to follow exactlyany final shape, the final shape being that targeted for a sheet. Thebands can be glued together, for example, by means of a fine layer ofelastomer or by means of a resin, rendering the sheets more monolithicin the latter case.

[0031] The invention thus extends to a method of manufacture of aresilient non-pneumatic tire having an axis of rotation and a bearingstructure having a median plane perpendicular to the axis of rotationand defining an inner cavity of revolution, the bearing structurecontaining a plurality of support elements distributed all around thecircumference, each support element being placed roughly crosswise, eachsupport element being a laminated element containing a stack ofresilient sheets superposed radially, a method in which the constituentsrequired for building the non-pneumatic tire are placed on adestructible support, and said method embracing, notably, the followingsteps:

[0032] bringing a section of the band on the support,

[0033] bending the section to make it follow exactly the shape of thesupport,

[0034] locking the ends of the section,

[0035] repeating the preceding stages until obtaining the stackingdesired.

[0036] In this first embodiment, in a laminated element 12, consideringthe length of the sheets in abscissa curvilinear on being displacedalong a sheet following an orientation going from one lateral end to theother lateral end, said length of each of the sheets 13 decreases onbeing displaced in thickness of the laminated element from the cavityoutward. This is what appears in FIGS. 1 and 3. Using this arrangement,the characteristics of resilience of the non-pneumatic tire can beadjusted by adapting the stack to the bending moment that it isnecessary to support locally and by adapting the stack to thedeflections it is desired to obtain.

[0037] Each laminated element, at least in the radially outer bearingstructure part, is preferably symmetrical and axially centered. Finally,let us point out that the zone of attachment 110 is preferably in onepiece, as can be seen in FIGS. 1 and 3. This means that this part,intended to be attached to a rim, does not present any laminatedstructure. For example, it contains only a resin matrix and reinforcingfibers, of course, preferably of the same component materials as thesheets, and it contains no rubber. This connection zone is so designedto undergo bending stresses.

[0038] After having described the main aspects of the architecture ofthe non-pneumatic tire, seen in meridian section, let us examine what isits architecture seen in circumferential section, referring for thispurpose to FIGS. 4 and 5. Also preferably, in a laminated element,considering that the width “1” is the dimension of the sheets beingdisplaced along a sheet following a circumferential orientation, thewidth 1 of the sheets is constant (see FIGS. 4 and 5, as well as FIGS.10 and 11, for the reader will have understood that this aspect, likemany others described, is also true for the other embodiments). It can,in fact, be simpler to manufacture only sheets of the same width. Ofcourse, as is evident on comparing FIGS. 4 and 5, since the width 1 ofthe sheets 13 is constant, the space between laminated elements 12 isless in the radially inner bearing structure part 11I than in theradially outer bearing structure part 11E.

[0039] Furthermore and still preferably, the width “1_(s)” of thesupport elements (considered circumferentially) is such that the numberof support elements in the whole circumference is at least 80. This isroughly drawn in FIGS. 10 and 11. This renders the tire sufficientlyuniform, although the bearing structure thus made cannot be consideredhomogeneous circumferentially, for example, for its modeling. Such abearing structure presents a cyclical symmetry, according to a standardterminology. To further improve uniformity, the number of supportelements can be increased and their width 1_(s) can be concomitantlydiminished in the circumference. The non-pneumatic tire according to theinvention is then advantageously such that, considering width 1_(s) thedimension of the support elements on being circumferentially displaced,the width 1_(s) is such that the number of support elements in the wholecircumference is at least in the order of 200.

[0040] In the radially outer bearing structure part, the proposedinterconnecting structure contains circumferential reinforcements atleast under the tread. They are, for example, circumferential wires 16that can be seen, notably, in FIGS. 1 and 4. Said wires ensure thestability of the dimensions of the non-pneumatic tire on centrifuging.Furthermore, said circumferential wires 16 help distribute the load of asupport element (laminated element 12) on the adjacent laminated elementor elements 12. If one can imagine, notably, what happens if a supportelement (laminated element 12) mounts an isolated obstacle, the latteris going to tend to be avoided, for the load tends to be applied only onthat laminated element instead of being distributed over severallaminated elements. As soon as the overloaded laminated element bendsmore than the adjacent ones, the circumferential wires 16 pull on theadjacent laminated elements 12, thus transferring a part of the load.This leads to a certain warping of the support elements. Said supportelements are designed so that they can sustain a certain degree ofwarping stress. The proposed embodiments, having laminated element 12with base pieces (resilient sheets 13) stacked radially with rubberlayer 15 inserted in between, are able to accommodate the encounteredwarping stress. But of course other embodiments are achievable. Thenon-pneumatic tire is thus capable of absorbing an isolated obstaclelike a stone on the road. Furthermore, the circumferential wires 16contribute to passage of the torque by distributing the stress over allthe laminated elements 12 on the whole circumference of thenon-pneumatic tire.

[0041] Furthermore, the proposed interconnecting structure also containsa rubber matrix 165 separating the sheets circumferentially (see FIG.4). The said interconnecting structure could contain only rubberensuring a connection between support elements, for example, forapplications of the invention to moderately stressed non-pneumatictires. In the example described, the rubber completely fills the spacebetween two adjacent laminated elements. In addition, a layer of rubbercompletely covers the structural reinforcements of the non-pneumatictire, thus creating a continuous outer skin like standard tires. Ofcourse, other variants can be developed, for example, devoid of rubberor with much less rubber radially under the circumferential wires 16.This can prove advantageous for attaining a lesser level of rollingresistance.

[0042] In the present application, the term “wire” is used in a genericsense, meaning that said wire is supposed to present characteristicssufficient to transfer a portion of the radial stress to the adjacentsupport elements and to transmit the load beyond the footprint. One canuse monofilaments, multifilaments or assemblages like cords or even anyequivalent structure, regardless of the material or materials of thosewires, their moduli and any treatment of those wires, like surfacetreatment or coating or precoating to favor adhesion on the rubber.“Circumferential” means an orientation at an angle of zero degreemeasured in relation to a plane perpendicular to the axis of rotation ofthe support, thus observing the usual conventions for tires. Inpractice, the reinforcement can be made by coiling of a wire, with acertain pitch, resulting in the angle not strictly being zero, but, inpractice, at least locally greater than zero degree, in order to be ableto sweep the entire width desired.

[0043] There is nothing imperative, however, about the arrangementsdescribed in the three foregoing paragraphs. The laminated elements canbe interconnected by layers of a nature similar to layers 13 of eachstack. Many other forms of interconnection can be carried out. In short,and to state the essentials, the laminated elements bear the load; theydo not work completely isolated from one another, but are connectedtogether to ensure good overall operation, avoiding overly intenseshearing between two adjacent laminated elements and so as to offer gooduniformity, that is, a relative constancy of properties, regardless ofthe circumferential position of the non-pneumatic tire relative to thesurface.

[0044] Returning to the connection between the radially outer bearingstructure part 11E and the radially inner bearing structure part 11I,which was said to form a sort of hinge 17, appreciably inextensibleradial wires 170, embedded in a rubber matrix, cover the junction of theouter side of the latter, in order to integrate correctly the radiallyinner bearing structure part and the radially outer bearing structurepart (see left portion of FIG. 1). These radial wires 170 are placed inthe zones of lesser bending strength and are embedded in a rubbermatrix. As a variant (see right portion of FIG. 1), each radial wire isplaced relative to the support elements of the inner cavity side on oneof the bearing structure parts (see wires 170 a and 170 c) and of theouter side on the other one of the bearing structure parts (see wires170 b and 170 d), some of the successive wires on said first radiallyinner bearing structure part being placed outside and the others beingplaced inside the inner cavity, preferably alternately.

[0045] In this first embodiment, the laminated elements 12 resemblecompound springs, except that here the sheets are fixed to one anotherby a layer of rubber. The radially inner and outer bearing structureparts 11I and 11E present, in the whole meridian plane, a quasisymmetryon both sides of a virtual cylinder passing through the hinges 17. Theradially outer and inner bearing structure parts 11E and 11I are soconstructed that each takes approximately half the deflection resultingfrom a loading, which is favorable to endurance of the zone forming ahinge, for deflection is possible with relative motion of the axial endsof the bearing structure parts. FIG. 3 shows the shape of thenon-pneumatic tire loaded.

[0046] It is to be understood that, in case of very considerableoverload, due, for example, to a shock against a sidewalk curb, theradially outer bearing structure part naturally abuts the radially innerbearing structure part. This occurs well before the laminated elementsmight have been bent to the breaking point. This is why thenon-pneumatic tire proposed in the invention contributes a very sturdysolution, offering good endurance under the effect of the most severestresses that might be encountered in normal service on a vehicle.

[0047] The non-pneumatic tire illustrating the first embodimentdescribed above contains laminated elements arranged roughly radially.As is known from operation of a standard radial tire, it is noted thatthe laminated elements accommodate a slightly non-radial orientation.That means that the reinforcing elements, which are normally radiallyoriented in the sidewalls (carcass cords in a conventional pneumaticradial tire, support elements in the described embodiments proposed inthis specification), leave somewhat their genuine radial orientation,the maximum value of deviation being observed on entry and on exit ofthe footprint. Consequently, passage into the footprint, in addition tobending, the support elements are subjected to torsion and stress. Thisdeviation with respect to the radial orientation is possible as thesupport elements are designed to accommodate deformations other thandeflection in a radial plane.

[0048] As for attachment on means of connection to a hub, the tire canbe attached to a wheel disk or any other member securing rigidfunctional connection with a hub. The tire and wheel assembly presents,in the manner known for pneumatic tires, a transverse rigiditysufficient to be able to guide a vehicle, notably, on turns. As far asthe non-pneumatic tire is concerned, one or more circumferentiallyinextensible reinforcements, for example, rigid hoops 18 for the firstembodiment, are placed in the zone of attachment and contribute to goodlocking of the tire on its rim in case of transverse stresses.

[0049]FIG. 6 illustrates a second embodiment, in which the non-pneumatictire profile, seen in meridian section, resembles the profile of a tiredesigned to work at small or zero camber angles (like passenger tires).The sidewalls are rounded and lie in almost all of the radial height ofthe non-pneumatic tire. The bearing structure essentially containslaminated elements 22 comprising a stack of resilient sheets 23,superposed and separated by layers of rubber 25; and embodies thesupport elements. An attachment zone 210 is arranged substantially inthe middle of the radially inward wall of the non pneumatic tire. Thesupport elements jump over the attachment zone and project beyond saidattachment zone, and as in the first embodiment are fitted so as to beable to undergo bending stresses.

[0050] The parameters of size and adjustment of properties of thenon-pneumatic according to this second embodiment are, notably, thosepreviously mentioned, namely, the thickness of layer 25 and each sheet23, the number of sheets, the modulus of elasticity of the elastomermaterials employed for the sheets, the modulus of elasticity of theelastomer used, and the arrangement of the sheets. Likewise, for thecomposition of the sheets 23, references should be made to theexplanations supplied for sheet 13. The non-pneumatic tire also containscircumferential reinforcements (not shown) under the tread.

[0051] The non-pneumatic tire contains a tread 21, which can be veryslightly bent when it is not supporting any load. The radially outerpart of the bearing structure, that is, the zone containing the tread 21and the part of the sidewalls 29 close to the tread 21, contribute onlyvery little to deflection (radially) under the effect of the load. Thesidewalls 29 and, in particular, the radially inner part of the latter,as well as the radially inner wall of the bearing structure, are theseat of deformations responsible for most of the deflection under load.The part of the radially inner bearing structure, which at zero load isappreciably straight (see FIG. 6), parallel to the axis of rotation,takes a bowed shape, the concavity of which is directed inward (see FIG.7), which is accompanied by a slight relative coming together of itslateral limits. This type of deformation applies to each of the lateralzones of the bearing structure under the tread, a moment tending totransfer the load to the central zone of the tread and concomitantly torelieve the shoulders of the tire, which on the whole makes it possibleto ensure a relative constancy of pressures on the surface in thefootprint.

[0052] Just as in the first embodiment, the tire is attached to a wheeldisk or to any other member ensuring rigid functional connection with ahub. The assembly presents, in the median zone of the radially innerwall of the bearing structure, a transverse rigidity sufficient to beable to guide a vehicle, notably, on turns.

[0053] Let us further note that the properties of the non-pneumatic tirecan be adjusted by working on the design of the means of connection tothe hub of the non-pneumatic tire, called “rim” for sake of convenience.By more or less widening the bearing surface 291, preferablysymmetrically, the radial resilience of the non-pneumatic tire can beadjusted, somewhat like the inflation pressure of a pneumatic tire,which is adjusted for a tire of the same model according to the vehicleequipped, according to the axle of the vehicle and according to whetherthe vehicle is used loaded or empty. Therefore, depending on the rimused, the radial resilience of the tire mounted on its rim varies.

[0054] The invention extends to a rim intended to be used with adeformable non-pneumatic tire designed as explained above, said rimcontaining mounting means for receiving and locking said zone ofattachment of the tire and containing, on at least one side axially (andpreferably on both sides), a seat extending roughly parallel to saidzone of attachment of the non-pneumatic tire, in which the axialposition of the axially outermost point 284 still in contact with thenon-pneumatic tire is adjustable (see FIG. 7, it being known that saidbearing surface is located axially between the axially outermost points284, or 384 in FIG. 9). In this way, the bearing surface 291 of the tireon the rim can be varied. All along the bearing surface, the wall of thetire cannot be radially displaced toward the axis of rotation, whichalters operation of the tire wheel.

[0055]FIGS. 8 and 9 illustrate a third embodiment very similar to thesecond. A tread 31 and support elements 32 are provided. Theinterconnecting structure contains circumferential reinforcements 36 insheet form. The zone of attachment is circumferentially slotted (notshown in the simplified views of FIGS. 10 and 11), so that thenon-pneumatic tire presents two connecting ribs 320, capable of beingaxially displaced relative to each other. Said connecting ribs 320 areeach intended to come in contact with the said means of connection to ahub, notably, through a contact bearing 391 on the radially inner sideof each of the connecting ribs 320. Said ribs are the attachment zonereferred to hereinabove.

[0056] It can be seen in FIG. 8 that the latter resembles a narrow rimdesigned to grip said connecting ribs 320 by means of a profiled part321 of suitable shape. A wheel disk 38 extended by a first flange 380can be seen. A second flange 381 is mounted on the disk 38 by means ofscrews and nuts 382, with insertion of the profiled part 321 andconnecting ribs 320 of the non-pneumatic tire. The profiled part 321 isa rotating piece whose meridian section is clearly visible in FIGS. 8and 9, and which can be slotted and therefore interruptedcircumferentially, so as to facilitate its insertion between the ribs320 of the non-pneumatic tire. Next, the non-pneumatic tire, with theprofiled part inserted between the ribs 320, is correctly positionedrelative to the first flange 380, and then the second flange 381 isfastened on the first, with interposition of the profiled part. Part 321makes it possible, with the first and second flanges 380 and 381, togrip the connecting ribs 320, so that the non-pneumatic tire is fittedon the means of connection to the hub, which is the preferred mountingof the non-pneumatic tire.

[0057] Thus, the invention also extends to a rim containing mountingmeans for receiving and locking a resilient non-pneumatic tire having anaxis of rotation and essentially containing a tread carried by aresilient bearing structure radially situated inside said tread anddefining, at least partially, an inner cavity of revolution, saidbearing structure embracing a zone of attachment radially on the side ofthe axis of rotation, for the locking of said bearing structure on meansof connection to a hub, said means of connection to a hub forming arigid assembly, said zone of attachment being placed axially between thelateral limits of said bearing structure, and said zone of attachmentbeing circumferentially slotted, so that the tire presents twoconnecting ribs 320, capable of being axially displaced in relation toeach other, said rim including:

[0058] two flanges 380, 381, each serving as seat for one of the tworibs 320,

[0059] a profiled shape 321 designed to cooperate with said flanges 380,381 in order to grip said ribs 320 and to lock them on the rim.

[0060] The form of manufacture of the non-pneumatic tire can bedifferent from the form of use required by the means of connectiontaking the place of a rim. For example, the connecting ribs 320 can beforced to come together axially on mounting. The widened shape of theconnecting ribs 320, forming a sort of dovetail, helps avoid anyaccidental demounting of the tire under the effect of the prestressinginstalled in same. The resilience can thus be adjusted by a preload inthe laminated elements 32 according to the relative axial separationbetween the connecting ribs 320 of the non-pneumatic tire.

[0061] Furthermore, just as already explained above, depending on thesize of the contact bearing 391, it is possible to act on the deflectionby the non-pneumatic tire. Supplementary rings 383 can also be added towiden the bearing surface of the non-pneumatic tire for the purposementioned above (see bearing 391 b in FIG. 9).

[0062] Finally, FIGS. 10 and 11 represent the general shape of theresilient bearing structure. Comparison of those figures shows thedeflection obtained with a non-pneumatic tire according to theinvention. A certain degree of deviation with respect to the radialorientation exists in all the embodiments. This is notably evident atthe bottom of FIG. 11, by carefully observing the bent zone D, where itcan be seen that the deflection of the support elements come with acertain degree of warping, the more the support element is offset of thesection plane of FIG. 11 while bending in the footprint, the greater thedeviation is.

[0063] In the examples illustrating this specification, the supportelements take the form of laminated elements. The bundle of base piecesis therefore formed by a stack of sheets, with insertions of rubber,whatever the construction of the sheets themselves. In light of thefollowing description, the function of these support elements will morereadily appear, and the person of skill in the art will, of course, beable to substitute those laminated elements with other forms ofconstruction, that is, substitute the sheets with other forms for thebase pieces, provided that the support elements offer the radialflexibility sought and make the required contribution to take-up of theload and are also capable of offering suitable characteristics inresponse to the nonradial stresses seated in such non-pneumatic tires(transmission of so-called “X” and “Y” stresses) and of working inharmony with the adjacent support elements. In other words, the bearingstructure, on being deformed, makes possible a certain flattening of thezone under the tread concerned on contact with the surface, so that thetrack of the loaded tire on the surface takes a certain form, as in thewell known operation of inflated tires.

[0064] Each support element is present at least in the part of thebearing structure lying between the lateral ends of said bearingstructure and the tread and not necessarily under the tread, although inthe examples described said support elements are continuous under thetread. One could, however, as a variant and at least under a substantialpart of the tread, replace the stack of sheets, that is, the bundle ofbase pieces, with a rather rigid ring of the type proposed asreinforcement under the tread in U.S. Pat. No. 4,111,249. The stack ofsheets can also be replaced with a relatively rigid stud; a large numberof studs are arranged circumferentially, the set of studs beingarticulated with one another and thus forming a sort of circumferentialtrack (see, for example, the reinforcing structure under the treaddescribed in patent application EP 0,836,956). More generally speaking,any structure could thus be placed under the tread, provided that it iscapable of transferring a shear to the lateral parts of thenon-pneumatic tire.

[0065] In all the variants proposed, the part of the radially innerbearing structure closest to the axis of rotation makes an importantcontribution to the deflection under load and, therefore, to the comfortprovided by the tire. Hence, it is advisable for the zone of attachmentto be located preferably on a fraction corresponding to not more than50% of the distance axially separating the lateral limits of thenon-pneumatic tire. Said radially inner part of the resilient bearingstructure thus rather markedly projects beyond the zone of attachment. Afavorable structural arrangement is for the support elements to beoriented, just beyond the zone of attachment, in a direction roughlyparallel to the axis of rotation. This is what appears in the examplesdescribed below. Finally, the non-pneumatic tires described beingsymmetrical, the zone of attachment is roughly centered between theaxial limits of said non-pneumatic tire, without this being limitative.A dissymmetrical architecture could, of course, be adopted, notably, inthe location of the zone of attachment.

[0066] As for the degree of contribution to the deflection under load ofthe part of the radially outer bearing structure, it can vary with theembodiments.

[0067] In the first example proposed, the bearing structure contains afirst radially inner bearing structure part and a second radially outerbearing structure part, said first and second bearing structure partsbeing integrated with each other by a zone of lesser bending strength,each of said first and second bearing structure parts containing saidsupport elements, and each support element of the first radially innerbearing structure going at least from a lateral end to said zone ofattachment, so that the zones of lesser bending strength between thefirst and second bearing structure parts are, under the effect of theworking stresses, radially mobile in relation to the zone of attachment.Each support element of the second radially outer bearing structurepreferably goes from one lateral end to the other lateral end of saidsecond bearing structure part.

[0068] The radially inner bearing structure part forms two zones whichoverhang the rigid central connection. According to the invention, thesetwo zones fully share in the flexibility of the non-pneumatic tire. Thisis what it was intended to express above on stating that the zones oflesser bending strength are, under the effect of the working stresses,radially mobile in relation to the zone of attachment. This has oneclear consequence, valid moreover for all the embodiments: to permitefficient operation of the non-pneumatic tire according to theinvention, no obstacle should prevent elastic deformation radiallyinward from the radially inner bearing structure part, that is, the partleading to said rigid central connection. The latter, on bending, comessomewhat close to the axis of rotation. The shape of the non-pneumatictire on maximum bending therefore dictates a limiting casing inside ofwhich one cannot encounter any of the mechanical parts of the vehicle:wheel disk and/or rim, braking parts, suspension parts, etc.

[0069] In the first of the examples illustrated, the degree ofcontribution to deflection under load of the radially outer bearingstructure part is roughly equivalent to the degree of contribution todeflection under load of the radially inner bearing structure part. Ofcourse, said zone of lesser bending strength can be less localized andcan involve a greater portion of the wall of the bearing structure.

[0070] In a second embodiment, the support elements are continuous inthe sidewall of the tire. The contribution to deflection is due mainlyto the bearing structure part situated radially inward. It can be seen,in FIGS. 6 and 7, that the deflection due to loading leads to a decreaseof the radius of curvature of the support elements: “R” in FIG. 6,showing the unloaded non pneumatic tire, is greater than “r” in FIG. 7,showing the loaded non pneumatic tire.

[0071] Turning to the mounting of the non-pneumatic tire proposed by theinvention, in the case of a standard tire, it is known that the rim hasroughly the width of the tire. Here, on the other hand, thenon-pneumatic tire projects widely on both sides of the centralmechanical part taking the place of a rim, which has been more generallydescribed in the introduction to the invention by the more functionalexpression “means of connection to a hub.” Said means can take highlyvaried forms. It can involve a disk similar to a wheel disk, ending in arevolving part, the meridian profile of which is an open groove towardthe wider radii, made, for example, in two parts in order to be able totighten a rib of the non-pneumatic tire having a complementary shape. Itcan also involve a wheel of the type described in U.S. Pat. No.5,071,196, that is, without any disk. In short, to state the essentials,said means of connection to a hub are rigid, as is the wheel with itsrim in the current state of the art.

[0072] As for the material constituting the base pieces, it isadvantageously a composite material, that is, a combination of differentmaterials. The support elements illustrated here are laminated elements.The geometry of the support elements makes it possible to offer them theresilience desired without attaining the breaking points or elasticlimit to the deformations encountered. Each of the sheets is very narrowin order to offer a substantial deflection. Each one is able toaccommodate small radius on bending. None is capable of alone bearingthe nominal load sought. By multiplying the sheets, their contributionto support the load are added. The sheets are integrated with oneanother by the rubber adhering to said sheets. Due to a stacking of somevery thin sheets, a sufficient bearing is obtained, while being able toattain very high deflection.

[0073] The architecture of the tire proposed makes it possible tomanufacture tires designed to operate without inflation pressure(non-pneumatic tire). Note, and this is important, nothing preventsimparting a certain air pressure to the proposed tire. It is sufficient,of course, to arrange for the tire to be airtight. An adequate skin isadded to the bearing structure, which is useful in any case to preventfouling of the inner cavity. The characteristics, resilience, notably,can then be adjusted by working with pressurization of the inner cavity.In doing a comparison with a inflated pneumatic tire, the pressurizationreferred to here is related to the variations around the rated pressurefor which the pneumatic tire is designed. That is to say that, ifaccording to the final destination of a pneumatic tire on differentspecific cars, the tire is used at pressure ranging from P to P+ΔP, thenon pneumatic tire in accordance with this invention can be actuallyused in the range of 0 (no pressure at all) to 0+ΔP. But this is onlyone means of adjustment among others that are more structural, whichhave been explained, the non-pneumatic tire of this invention havingbeen actually assigned to work at zero pressure in normal operation.

[0074] One advantage of the present invention is to propose anarchitecture which makes it possible, in particular, both to bear thedesired load and to absorb without damage very isolated obstacles like astone on the road.

[0075] Another advantage of the invention is to ensure, other than bytightening of a bead on a rim, the connection between the tire and therim or the part or parts taking the place of a rim in order to give thereference that is the axis of rotation. This results in a saving ofmaterials and, therefore, a weight advantage of this tire portion.

[0076] It has been seen that the resilient non-pneumatic tire includes abearing structure, a tread radially outside the bearing structure andmeans of attachment to a rigid rim or to an equivalent mechanical part.It has also been seen that the bearing structure has a plurality ofsupport elements juxtaposed and distributed all around thecircumference, each support element being placed in a mainly transverseand generally radial orientation, so that each support elementsuccessively enters into play to transfer a fraction of the load of thenon-pneumatic tire from the tread to the hub, when the tire is rollingand is loaded, transfer of the load subjecting each element essentiallyto bending stress. Moreover, it has been observed, with the embodimentsaccording to FIGS. 6 to 11, that upon increase of the transversalstresses as occurring for example in turns, a slight decrease of theradial deflection occurs, providing an anti-noll effect.

[0077] In short, the support elements advantageously consist oflaminated elements including a stack of resilient sheets, the resilientsheets being radially superposed and separated by a layer of elastomeradhering to each of the sheets, bending of the laminated elements beingaccompanied by a relative tangential displacement between sheets and bya shear stress of the elastomer, each laminated element being radiallyresilient under the effect of the working stresses, the bending of alaminated element transferring a moment to said means of attachment. Inaddition, it has been seen that the bearing structure includes means ofinterconnection between the support elements (the laminated elements),arranged so that a portion of the radial stress of the support elementsis transferred to the circumferentially adjacent laminated elements,while allowing differences in displacement between adjacent laminatedelements. These means of interconnection can involve the supportelements over their whole length or only over part of same, particularlyunder the tread. The bearing structure is so arranged that, when theradial deflection taken by the non-pneumatic tire brings the radiallyouter part of the bearing structure against the zone of attachment tothe rim (immobile), the resulting stresses due to bending in the supportelements are less than the breaking point (and are less than the elasticlimit if a material having an elastic limit less than the breaking pointis included in the composition of the base pieces).

We claim:
 1. A resilient non-pneumatic tire having an axis of rotationand a tread carried by a resilient bearing structure radially situatedinside said tread and defining, at least partially, an inner cavity ofrevolution, said bearing structure comprising: a zone of attachmentradially on the side of the axis of rotation for the locking of saidbearing structure on means of connection to a hub, and said zone ofattachment being axially placed between lateral limits of said bearingstructure, said attachment zone being designed for contacting said meansof connection to a hub, said means of connection to a hub being designedto form a rigid assembly, a plurality of support elements, extendingessentially crosswise, placed between the zone of attachment and thetread, said support elements being juxtaposed circumferentially anddistributed all around the circumference, the support elements beingfitted in said zone of attachment, each support element including abundle of superposed resilient base pieces, separated by a layer ofelastomer adhering to each of the base pieces, so as to form a beamcapable of undergoing bending stress, an interconnecting structurebetween the support elements arranged so that a portion of a radialstress of a support element is transferred to the adjacent supportelements circumferentially, while allowing differences in displacementbetween adjacent support elements.
 2. A non-pneumatic tire according toclaim 1, in which the zone of attachment is located on a fractioncorresponding to not more than 50% of the distance axially separatingthe said lateral limits.
 3. A non-pneumatic tire according to claim 1,in which the said support elements are continuous under the tread.
 4. Anon-pneumatic tire according to claim 1, in which the base pieces aremade of composite material.
 5. A non-pneumatic tire according to claim1, in which the support elements are, just beyond the zone ofattachment, oriented in a direction roughly parallel to the axis ofrotation.
 6. A non-pneumatic tire according to claim 1, in which thezone of attachment is roughly centered between the axial limits of saidtire.
 7. A non-pneumatic tire according to claim 1, in which the zone ofattachment is in one piece.
 8. A non-pneumatic tire according to claim1, in which the bearing structure includes a first radially innerbearing structure part and a second radially outer bearing structurepart, said first and second bearing structure parts being integratedwith each other by a zone of lesser bending strength, each of said firstand second bearing structure parts containing said support elements, andeach support element of the first radially inner bearing structureextending at least from a lateral end to said zone of attachment, sothat the zones of lesser bending strength between the first and secondbearing structure parts are, under the effect of the working stresses,radially mobile in relation to the zone of attachment.
 9. Anon-pneumatic tire according to claim 8, in which each support elementof the second radially outer bearing structure extends from one lateralend to the other lateral end of said second bearing structure part. 10.A non-pneumatic tire according to claim 8, in which each support elementof the first radially inner bearing structure part extends from onelateral end to the other lateral end.
 11. A non-pneumatic tire accordingto claim 8, in which a meridian section of the first radially innerbearing structure part has a general bow shape, the concavity of whichis oriented radially outward.
 12. A non-pneumatic tire according toclaim 8, in which the meridian section of the second radially outerbearing structure part has a general bow shape, the concavity of whichis oriented radially inward.
 13. A non-pneumatic tire according to claim8, in which the ends of each of the first and second bearing structureparts are situated roughly at the lateral limits of the bearingstructure.
 14. A non-pneumatic tire according to claim 8, in which thezones of lesser bending strength contain inextensible radial wiresembedded in a rubber matrix.
 15. A non-pneumatic tire according to claim14, in which each radial wire is placed relative to the support elementsof the inner cavity side on one of the bearing structure parts and ofthe outer side on the other one of the bearing structure parts, some ofthe successive wires on said first radially inner bearing structure partbeing placed outside and the others being placed inside the innercavity.
 16. A non-pneumatic tire according to claim 8, in which, in asupport element, considering the length of the base pieces in abscissacurvilinear, the length of each of the base pieces decreases on beingdisplaced in thickness of a support element from the cavity outward. 17.A non-pneumatic tire according to claim 1, in which the zone ofattachment is circumferentially slotted, so that the tire presents twoconnecting ribs, capable of being axially displaced relative to eachother.
 18. A non-pneumatic tire according to claim 1, in which in thepart of a support element situated under the tread, considering thelength of the base pieces in abscissa curvilinear, the length of each ofthe base pieces increases on being displaced in thickness of a supportelement from the cavity outward.
 19. A non-pneumatic tire according toclaim 1, in which each of the base pieces is a resilient sheet, so thateach support element forms a laminated element containing a stack ofsaid resilient sheets.
 20. A non-pneumatic tire according to claim 19,in which, in a laminated element, considering width 1 the dimension ofthe sheets on being displaced along a sheet following a circumferentialorientation, the width of the sheets is constant.
 21. A non-pneumatictire according to claim 19, in which each sheet is formed by thesuperposition of bands affixed to one another.
 22. A non-pneumatic tireaccording to claim 19, in which the sheets are formed from athermosetting or thermoplastic resin matrix, reinforced by fibers mainlyplaced longitudinally in each sheet.
 23. A non-pneumatic tire accordingto claim 1, in which, considering that width 1_(s) is the dimension ofthe support elements on being circumferentially displaced, width 1_(s)is such that the number of support elements in the whole circumferenceis at least
 80. 24. A non-pneumatic tire according to claim 1, in which,considering that width 1_(s) is the dimension of the support elements onbeing circumferentially displaced, width 1_(s) is such that the numberof support elements in the whole circumference is at least
 200. 25. Anon-pneumatic tire according to claim 1, in which the interconnectingstructure includes circumferential reinforcements at least under thetread.
 26. A non-pneumatic tire according to claim 1, in which theinterconnecting structure contains a rubber matrix separating thesupport elements circumferentially.
 27. A non-pneumatic tire accordingto claim 1, in which the support elements are arranged roughly radially.28. A non-pneumatic tire according to claim 1, in which the zone ofattachment includes at least one reinforcement circumferentiallyinextensible.
 29. A rim for a non-pneumatic tire according to claim 1,including mounting means for receiving and locking said zone ofattachment of the tire and, on at least one side axially, a seatextending roughly parallel to said zone of attachment of the tire, inwhich the axial position of the axially outermost point in contact withthe tire is adjustable.
 30. A rim including mounting means for receivingand locking a resilient non-pneumatic tire having an axis of rotationand a tread carried by a resilient bearing structure radially situatedinside said tread and defining, at least partially, an inner cavity ofrevolution, said bearing structure embracing a zone of attachmentradially on the side of the axis of rotation, for the locking of saidbearing structure on means of connection to a hub, said means ofconnection to a hub forming a rigid assembly, said zone of attachmentbeing placed axially between lateral limits of said bearing structure,and said zone of attachment being circumferentially slotted, so that thetire presents two connecting ribs capable of being axially displaced inrelation to each other, said rim comprising: two flanges, each servingas a seat for one of the two ribs, a profiled shape which cooperateswith said flanges in order to grip said ribs and to lock them on therim.
 31. A rim according to claim 30, including supplementary ringswhich widen the surface of support of the non-pneumatic tire on the rim.32. In the manufacture of a resilient non-pneumatic tire having an axisof rotation and including a bearing structure having a median planeperpendicular to the axis of rotation and defining an inner cavity ofrevolution, the bearing structure including a plurality of supportelements distributed all around the circumference, each support elementbeing placed roughly crosswise, each support element being a laminatedelement containing a stack of resilient sheets superposed radially, amethod in which the constituents required for making the non-pneumatictire are placed on a destructible support, said method comprising:bringing a section of the bands on the support, bending the section tomake it follow exactly the shape of the support, locking the ends of thesection, repeating the preceding steps until obtaining the stackingdesired.
 33. A resilient non-pneumatic tire having an axis of rotationand essentially having a tread carried by a resilient bearing structureradially situated inside said tread and delimiting, at least partially,an inner cavity of revolution, said bearing structure comprising: a zoneof attachment radially on the side of the axis of rotation, for thelocking of said bearing structure on means of connection to a hub, saidmeans of connection to a hub forming a rigid assembly, a plurality ofsupport elements, extending essentially crosswise, placed between thezone of attachment and the tread, said support element being juxtaposedcircumferentially and distributed all around the circumference, eachsupport element containing a bundle of superposed resilient base pieces,separated by a layer of elastomer adhering to each of the base pieces,so as to form a beam capable of undergoing bending stress, aninterconnecting structure between the support elements, arranged so thata portion of a radial stress of a support element is transferred to theadjacent support elements circumferentially, while allowing differencesin displacement between adjacent support elements, said support elementsand interconnecting structure being designed for a zero pressureoperation of said tire.
 34. A non-pneumatic tire according to claim 33,in which the said support elements are continuous under the tread.
 35. Anon-pneumatic tire according to claim 33, in which the base pieces aremade of composite material.
 36. A non-pneumatic tire according to claim33, in which the support elements are, just beyond the zone ofattachment, oriented in a direction roughly parallel to the axis ofrotation.
 37. A non-pneumatic tire according to claim 33, in which thezone of attachment is roughly centered between the axial limits of saidtire.
 38. A non-pneumatic tire according to claim 33, in which the zoneof attachment is in one piece.
 39. A non-pneumatic tire according toclaim 33, in which the bearing structure includes a first radially innerbearing structure part and a second radially outer bearing structurepart, said first and second bearing structure parts being integratedwith each other by a zone of lesser bending strength, each of said firstand second bearing structure parts containing said support elements, andeach support element of the first radially inner bearing structureextending at least from a lateral end to said zone of attachment, sothat the zones of lesser bending strength between the first and secondbearing structure parts are, under the effect of the working stresses,radially mobile in relation to the zone of attachment.
 40. Anon-pneumatic tire according to claim 39, in which each support elementof the second radially outer bearing structure extends from one lateralend to the other lateral end of said second bearing structure part. 41.A non-pneumatic tire according to claim 39, in which each supportelement of the first radially inner bearing structure part extends fromone lateral end to the other lateral end.
 42. A non-pneumatic tireaccording to claim 39, in which a meridian section of the first radiallyinner bearing structure part has a general bow shape, the concavity ofwhich is oriented radially outward.
 43. A non-pneumatic tire accordingto claim 39, in which the meridian section of the second radially outerbearing structure part has a general bow shape, the concavity of whichis oriented radially inward.
 44. A non-pneumatic tire according to claim39, in which the ends of each of the first and second bearing structureparts are situated roughly at the lateral limits of the bearingstructure.
 45. A non-pneumatic tire according to claim 39, in which thezones of lesser bending strength contain inextensible radial wiresembedded in a rubber matrix.
 46. A non-pneumatic tire according to claim45, in which each radial wire is placed relative to the support elementsof the inner cavity side on one of the bearing structure parts and ofthe outer side on the other one of the bearing structure parts, some ofthe successive wires on said first radially inner bearing structure partbeing placed outside and the others being placed inside the innercavity.
 47. A non-pneumatic tire according to claim 39, in which, in asupport element, considering the length of the base pieces in abscissacurvilinear, the length of each of the base pieces decreases on beingdisplaced in thickness of a support element from the cavity outward. 48.A non-pneumatic tire according to claim 33, in which the zone ofattachment is circumferentially slotted, so that the tire presents twoconnecting ribs, capable of being axially displaced relative to eachother.
 49. A non-pneumatic tire according to claim 33, in which in thepart of a support element situated under the tread, considering thelength of the base pieces in abscissa curvilinear, the length of each ofthe base pieces increases on being displaced in thickness of a supportelement from the cavity outward.
 50. A non-pneumatic tire according toclaim 33, in which each of the base pieces is a resilient sheet, so thateach support element forms a laminated element containing a stack ofsaid resilient sheets.
 51. A non-pneumatic tire according to claim 50,in which, in a laminated element, considering width 1 the dimension ofthe sheets on being displaced along a sheet following a circumferentialorientation, the width of the sheets is constant.
 52. A non-pneumatictire according to claim 50, in which each sheet is formed by thesuperposition of bands affixed to one another.
 53. A non-pneumatic tireaccording to claim 50, in which the sheets are formed from athermosetting or thermoplastic resin matrix, reinforced by fibers mainlyplaced longitudinally in each sheet.
 54. A non-pneumatic tire accordingto claim 33, in which, considering that width 1_(s) is the dimension ofthe support elements on being circumferentially displaced, width 1_(s)is such that the number of support elements in the whole circumferenceis at least
 80. 55. A non-pneumatic tire according to claim 33, inwhich, considering that width 1_(s) is the dimension of the supportelements on being circumferentially displaced, width 1_(s) is such thatthe number of support elements in the whole circumference is at least200.
 56. A non-pneumatic tire according to claim 33, in which theinterconnecting structure includes circumferential reinforcements atleast under the tread.
 57. A non-pneumatic tire according to claim 33,in which the interconnecting structure contains a rubber matrixseparating the support elements circumferentially.
 58. A non-pneumatictire according to claim 33, in which the support elements are arrangedroughly radially.
 59. A non-pneumatic tire according to claim 33, inwhich the zone of attachment includes at least one reinforcementcircumferentially inextensible.